Nitrile compounds



United States Patent 3,012,058 NITRILE COMPOUNDS Murray Hauptschein, Glenside, Pa., assignor' to Pennsalt Chemicals Corporation, Philadelphia, Pa., a corporation of Pennsylvania No Drawing. Filed May 15, 1958,,Ser. No. 735,648

3 Claims- (Cl. 260-463 This invention relates to para-substituted Z-trifluoromethylbenzonitriles represented by the formula wherein R includes chlorine, amino and hydroxyl radicals. Particularly this invention relates to the compounds 4- chloro 2 trifiuoromethylbenzonitrile (I), 4-amino-2-trifluoromethylbenzonitrile (H) and more particularly to 4- hydroxy-Z-trifiuoromethylbenzonitrile (*III) having formulas as shown in Table I.

TABLE I '0 1 (IJFS (IJF: $15:

. ON ON 0N 01-0 Hot-O Hog (II) (In nol:

CFs

HO HO 4-hydroxy-2-trifluoromethy1benzonitrile is also prepared from 4-chloro2-t1ifluoromethy1aniline by the steps of diazotization followed by cyanation to 4-chloro-2-trifiuoromethylbenzonitrile, amination to 4-amino-2-trifluoromethylbenzonitrile and diazotization of the latter compound and replacement of the amino group by hydroxyl to form said 4-hydroxy-2-trifluoromethylbenzonitrile, as shown in the following equations:

or, or.

The intermediate compounds, 4-chloro-2-trifluoromethylbenzonitrile and 4-aminc-2-trifluoromethylbenzonitrile, are also novel compounds.

The preparation of 4-hydroxy-2-trifluoromethylbenzo- CFa nitrile is demonstrated in the following examples which are presented for the purpose of illustrating the inven tion. It is to be understood that the invention is not intended to be restricted to these examples.

Example 1 4-HYDROXY-2 TRIFLUOROMETHYLBENZONITRILE Two grams of 4-amino-3-trilluoromethylphenol were dissolved in a solution of 8 ml. of concentrated sulfuricacid and 6 ml. of water and then diazotized at 0' Q with a solution of 0.8 g. of sodium nitrite in 5 ml. of water. The cold diazonium solution was treated with potassium nickel'ocy-anide by Sandemeyer procedure. The black precipitate (1.6 g.) was dissolved in hot water, decolorized with charcoal, and filtered. The filtrate was cooled in an ice-bath and 0.63 g. (30%) of fine white needles of 4-hydroxy-2-trifluoromethylbenzonitrile, MP.

119-120" C. was collected.

Anal.----Oalcd. for C H ONF C, 51.35; H, 2.15; N,- 7.49. Found: C, 51.51; H, 2.30; N, 7.46. p

Another method of preparation is as follows:

i Example 2 4-cHLOR0-2-TRIFLUOROMETHYLBENZONITRILE To 78.2 g. (0.4 mole) of 4-chloro-2-trifiuoromethylaniline, B.P. 84 C. at 10 mm., in 133 ml. of cold concentrated sulfuric acid, a cold 20% solution of sodium nitrite (27.6 g.) was added gradually with virgorous shaking. The diazonium solution was then added to potassium nickelocyanide as described above. On steam distil lation, 34.46 g. (42%) of 4-chloro-2-trifluoromethylbenzonitrile was collected, essentially all of which boiled at 109 C. at 10 mm. n 1.4902.

AnaL-Calcd. for C H NClF C, 46.74; H, 1.47; N, 6.81. Found: C, 47.26; H, 1.74; N, 6.45.

Example 3 4-AMINO-2-TRIFLUOROMETHYLBENZONITRILE 4-chloro-2-trifiuoromethylbenzonitrile prepared according to Example 2, aminated with an excess of liquid ammonia in a stainless steel pressure reactor at C. There was isolated in ca. 50% yield 4-amino-2-trifluoromethylbenzonitrile, M.P. 142 C. (recrystallized from water).

Anal.Calcd. for C H N F C, 51.62; H, 2.71. Found: C, 52.07; N, 3.15.

Example 4 4-HYDROXY-2-TRIFLUOROMETHYLBENZONITRILE Ninety-three hundredths gram (0.005 mole) of 4-amin0-2-trifluoromethylbenzonitrile prepared according to Example 3 was diazotized in a solution of 10 ml. of concentrated sulfuric acid and 20 ml. of water with 0.35 g. of sodium nitrite in 5 ml. of water. The diazonium solution was added in portions to a refluxing solution of 5 m1. of concentrated sulfuric acid and 40 ml. of water. The solution was refluxed for hour, cooled in ice, and 0.79 g. of crude material was recovered after separation of a red dye was made mechanically. On recrystallization from hot water (decolorized with charcoal) 0.6 g. (64%) of pure white 4-hydroxy-2-trifluoromethylbenzonitrile, M.P. 119-112 C. was recovered.

4-hydroxy-2-trifluoromethylbenzonitrile is particularly useful as a pesticide for warm-blooded pests, especially rats. In this service the compound is highly toxic, more so than is benzonitrile, due to the presence of the trifiuoromethyl group in addition to the cyano group in the molecule. Furthermore, the compound is a water-soluble crystalline product which is practically odorless. These properties are advantageous in the preparation and distribution of 4-hydroxy-2-trifluoromethylbenzonitri1e as a rodenticide in baits.

The use of 4-hydroxy-2-trifiuoromethylbenzonitrile as a rodenticide in a rat' bait is demonstrated by the following example. I

. Examplefi An aqueous solution containing about 0.75 lb, of 4- hydroxy-2-trifluoromethylbenzonitrile per quart of water is prepared and used as a rodenticide in the following bait for Norway rats:

Ground White breadcrumbs lbs 40 Breakfast rolled oats lbs; 40 Fish oil qt 1 4-hydroxy-2-trifiuoromethylbenzonitrile solution qt 1 In preparing the above bait, the solution of 4-hydroxy- 2-trifluoromethylbenzonitrile is mixed into the bread crumbs and rolled oats. The mixture is allowed to dry. The dried mixture is then blended with the other inm i s. .7 r

The mixed bait is distributed in areas infested by rats, care being taken that other animals, e.g., cats and dogs, do not have ready access to the bait. Upon ingestion of the bait, the 4-hydroxy-2-trifiuoromethylbenzonitrile is absorbed into the blood stream, where the effect is toxic, resulting in the death of the rat. 7

The intermediary compounds of this invention, 4- chloro 2 trifluoromethylbenzonitrile and 4-amino-2-trifluoromethylbenzonitrile are also useful as pesticides for warm-blooded pests andcan be used, in the same way as 4-hydroxy-Z-trifluoromethylbenzonitrile, as a rodenticide s the latter compound to 4-amino-2-trifluoromethylbenzoby substituting them for the latter compound in the bait disclosed in Example 5.

Many diiferent embodiments of this invention may be made without departing from the spirit and scope of it, and it is to be understood that my invention includes also such embodiments and is not limited by the above description.

I claim: l

l. The method of preparing 4-hydroxy-2-trifluoromethylbenzonitrile which comprises the steps of diazotizing followed by cyanation of 4-chloro-2-trifluoromethylaniline to 4-ehloro-2-trifluoromethylbenzonitrile, amin'ating nitrile and diazotizing and then hyd-roxylating this latter compound to form said 4-hydroxy-2-trifluoromethylbenzonitrile.

2. The compound 4-hydroxy-2-trifiuoromethylbenzonitrile.

3. The compound 4-a-mino-2-trifluoromethylbenzoni' trile.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Hauptschein et al.: J.A.C.S., vol. 76, Feb. 1954, pages 1051-1054. 

1. THE METHOD OF PREPARING 4-HYDROXY-2-TRIFLUOROMETHYLBENZONITRILE WHICH COMPRISES THE STEPS OF DIAZOTIZING FOLLOWED BY CYANATION OF 4-CHLORO-2-TRIFLUOROMETHYLANILINE TO 4-CHLORO-2-TRIFLUOROMETHYLBENZONITRILE, AMINATING THE LATTER COMPOUND TO 4-AMINO-2-TRIFLUOROMETHYLBENZONITRILE AND DIAZOTIZING AND THEN HYDROXYLATING THIS LATTER COMPOUND TO FORM SAID 4-HYDROXY-2-TRIFLUOROMETHYLBENZONITRILE. 